CAST AI Upgrade & Migration

Overview

Upgrade CAST AI components: Helm charts for the agent/controller/evictor, Terraform provider version, and workload autoscaler. Includes rollback procedures for each component.

Prerequisites

• Current CAST AI components installed
• Staging cluster for testing upgrades first
• Helm and kubectl access
• Change management approval for production

Instructions

Step 1: Check Current Versions

# Helm chart versions
helm list -n castai-agent -o json | jq '.[] | {name: .name, chart: .chart, appVersion: .app_version}'

# Available versions
helm repo update
helm search repo castai-helm --versions | head -20

# Terraform provider version
grep "castai/castai" .terraform.lock.hcl
terraform providers

Step 2: Review Changelog

# Check CAST AI changelog for breaking changes
# https://docs.cast.ai/changelog/

# Check Terraform provider releases
# https://github.com/castai/terraform-provider-castai/releases

Step 3: Upgrade on Staging First

# Upgrade agent
helm upgrade castai-agent castai-helm/castai-agent \
  -n castai-agent --reuse-values

# Upgrade cluster controller
helm upgrade cluster-controller castai-helm/castai-cluster-controller \
  -n castai-agent --reuse-values

# Upgrade evictor
helm upgrade castai-evictor castai-helm/castai-evictor \
  -n castai-agent --reuse-values

# Upgrade workload autoscaler
helm upgrade castai-workload-autoscaler castai-helm/castai-workload-autoscaler \
  -n castai-agent --reuse-values

# Verify all pods restarted cleanly
kubectl get pods -n castai-agent -w

Step 4: Upgrade Terraform Provider

# Update version constraint in versions.tf
terraform {
  required_providers {
    castai = {
      source  = "castai/castai"
      version = "~> 7.5"  # Update to target version
    }
  }
}

# Upgrade provider
terraform init -upgrade
terraform plan -var-file=environments/staging.tfvars

# Review plan carefully for resource recreation
# Apply if plan looks safe
terraform apply -var-file=environments/staging.tfvars

Step 5: Validate After Upgrade

# Verify agent is online
curl -s -H "X-API-Key: ${CASTAI_API_KEY}" \
  "https://api.cast.ai/v1/kubernetes/external-clusters/${CASTAI_CLUSTER_ID}" \
  | jq '{agentStatus, name}'

# Verify autoscaler policies still applied
curl -s -H "X-API-Key: ${CASTAI_API_KEY}" \
  "https://api.cast.ai/v1/kubernetes/clusters/${CASTAI_CLUSTER_ID}/policies" \
  | jq '.enabled'

# Check for errors in new agent version
kubectl logs -n castai-agent deployment/castai-agent --tail=50 | grep -i error

Rollback Procedure

# Helm rollback to previous release
helm rollback castai-agent -n castai-agent
helm rollback cluster-controller -n castai-agent

# Terraform rollback
terraform plan -var-file=environments/staging.tfvars  # Review
# If needed, pin previous provider version:
# version = "= 7.4.2"
terraform init -upgrade
terraform apply -var-file=environments/staging.tfvars

Error Handling

Issue	Cause	Solution
Agent CrashLoop after upgrade	Breaking chart change	helm rollback to previous
Terraform plan shows destroy	Major provider version jump	Pin intermediate version
Policies reset after upgrade	Chart default values changed	Pass --reuse-values
Spot handler incompatible	Node format changed	Upgrade all components together

Resources

• CAST AI Changelog
• Terraform Provider Releases
• Helm Charts

Next Steps

For CI pipeline integration, see castai-ci-integration.